There are two bells that I am familiar with that have dual block patterns but not familiar with a triple pattern.
A pre-60 bell will have a smallblock v-8 pattern(Hemi and Poly and A engines) along with the L6 pattern and the post-62 with the 'new' A engine and /6.
Not too sure what would have been available in 61-62 with the 'new' /6 engine replacing the L6 and then still-current (but now) 'old' A pattern....could be a real odd-ball.